Confused about how chromosome numbers change before and after mitosis and meiosis? This Amoeba Sisters UPDATED video breaks down chromosome vs chromatid and shows how to count chromosomes and how they change in cell division, all...

Join the Amoeba Sisters as they introduce the cardiac conduction system! This video mentions conductive cardiac cells (focusing on pacemaker cells) in the SA and AV nodes and discusses general steps of spontaneous depolarization. It also...

Join Pinky and Petunia in a cell types review game! This review game focuses on comparing cell characteristics of animals, plants, fungi, "protists," archaea, and bacteria. Clues may include prokaryote/eukaryote, autotroph/heterotroph,...

In which Stan Muller subs for John Green and teaches you about energy and humanity. Today we discuss the ideas put forth by Alfred Crosby in his book, Children of the Sun. Historically, almost all of the energy that humans use has been...

The thing about European History is that it tends to leak out of Europe. Europeans haven't been great at staying put in Europe. As human beings do, the people of Europe were very busy traveling around to trade, to spread religion, and in...

In which John Green teaches you about the Little Ice Age. The Little Ice Age was a period of global cooling that occurred from the 13th to the 19th centuries. This cooling was likely caused by a number of factors, including unusual solar...

In different contexts, you might speak a different language or use different terms, grammar, gestures, etc. Code switching can help you learn languages, turn the tides of social interactions, use up mental energy, and affect healthcare...

In 1643, Johann Wirsung was shot and killed outside his home, but not before he named one of the men responsible. One rumor that has emerged over the years is the man was paid by one of Wirsung's former assistants, who claimed Wirsung...

There's a list of the 500 most powerful computers on Earth, and we're downloading the details on the top five.

In a small town in the French Alps, a lot of people started to get the neurodegenerative disease ALS. Could the culprit be mushrooms?

You've probably heard of fool's gold, and it might make you think of prospectors in old timey California seeking their fortunes. But there's another kind of fool's gold called chalcopyrite, and lucky for those that want to strike...

Between 1485 and 1551, England was hit by at least five epidemics of sweating sickness. But after that, the disease supposedly vanished off the face of the Earth. With fatality rates as high as 90% according to some sources (perhaps...

The Park Grass experiment at Rothamsted Research Centre in England is the world's longest-running ecological experiment. It's also the result of a sort of Victorian Stardew Valley, the enduring friendship between John Bennet Lawes and...

Ivermectin does not work against COVID-19. However, it is almost a miracle drug when it comes to treating parasites. Doctors want to know if they can use ivermectin to prevent malaria. Here's how it's going.

Antarctica is more than a continent-sized sheet of ice (and the penguins that live atop it). There's land, liquid water, and even life underneath all that ice. And scientists have built up a suite of tools to find all of it.

Small grains in the Murchison meteorite have been estimated to be 7 billion years old—much older than the Earth, and even the solar system.

In 2009, a man named Edwin Rist planned a museum heist. His target wasn't jewels, or fossils, or the Declaration of Independence. It was bird skins. It took just over a year for authorities to track him down, largely because the...

Do animals exercise? Think about it -- do animals need to lose weight, or train for their big migration? We'll look at a few definitions of exercise and see if animals meet the criteria for hitting the gym.

All crocodilians look more or less the same today, but to survive two different mass extinctions, they've had to change a lot. Here's how they pulled it off.

Rocky bodies like moons, asteroids, and comets are chock full of resources, from water, to helium-3, to rare earth elements. But how can we access them? Some scientists have proposed using microbes to aid in the mining of certain metals.

Correction

07:11 We made a conversion error! The asteroid in this sentence should be 95,000 meters or 95 km. The conclusion (water would be deadly hot and sterilized) is cor

rect.

Let's face it: The Earth is going to get...

The Sahara is rather famously a desert, but it wasn't always that way. And during the time of lush green forests, there were plenty of people who lived there, but they've been hard to study. However, new genetic analysis has given us...

The North American continent used to have deep roots extending far into the Earth's mantle. They melted. Here's how scientists think they disappeared.

Humans love to decorate, and that's been true for a long time. Early humans have been painting on the walls for tens of thousand of years, and their work helped us understand a lot about their world and our own. From Lascaux Cave in...